1. Field of the Invention
This invention relates generally to instruments for making recordings on chart paper, and more particularly, to a pen and ink reservoir made in one unit complete with a supply of ink, and disposable as a unit when the ink supply has become exhausted.
2. Description of the Prior Art
For many years, recording instruments have been known which write with some type of pen on a chart paper. The pen is supplied with ink from a reservoir through a capillary tube. More recently, other means for marking charts have been devised. Nevertheless, pen-and-ink writing still produces a chart which has a good appearance, is easily read, provides a variety of color choices for the mark, and is relatively inexpensive. It is somewhat inconvenient because of occasional need for refilling the ink reservoir. This can be tedious and, in addition to the hazard of spills and splashes during the refilling process, can also result in some erratic chart marking due to pen bleeding or skipping for a short period after the refilling is accomplished.
One effort to avoid the need for refilling, is disclosed in U.S. Pat. No. 4,017,871 issued Apr. 12, 1977 to Hubbard. That patent discloses a marker with a three-phase ink circuit, wherein the entire marker and ink reservoir and circuit can be thrown away, after use. That patent discloses four versions.
There are many chart recording instruments in use today where a disposable pen-reservoir, would be beneficial. An example is the Esterline Angus Series "A" direct writing recorder which has been marketed by Esterline Angus of Speedway, Indiana. Efforts by others, both before and since my present invention, have been relatively unsuccessful in producing a disposable pen-reservoir suitable for use in these recorders.
It is therefore an object of the present invention to provide a disposable pen-reservoir suitable for direct-writing chart recording instruments. It is a further object to provide such a pen-reservoir suitable for use in the above-mentioned Esterline Angus recorders to replace the conventional stationary reservoir and capillary pen unit currently in use in the field.